She will be going to hell.
Allah says in the Qur'an, chapter 3 verses 18-19:
"Allah witnesses that there is no deity except Him, and [so do] the angels and those of knowledge - [that He is] maintaining [creation] in justice. There is no deity except Him, the Exalted in Might, the Wise. Indeed, the religion in the sight of Allah is Islam. And those who ...
If she dies as a person who rejected Islam, she will enter Hell, eternally.
And whoever of you reverts from his religion [to disbelief] and dies while he is a disbeliever - for those, their deeds have become worthless in this world and the Hereafter, and those are the companions of the Fire; they will abide therein eternally.
— Quran 2:217
Allah the Almighty is all-forgiving, there isn’t a sin he will not forgive if you repent for that sin. The hadith you mentioned is non-existent and is spread to make people scared. But remember Allah and if you were to die whilst masturbating.
A small portion of Sahih Muslim 183:
It was asked: Messenger of Allah, what is this bridge? He said: The void in which one Is likely to slip. There would be hooks, tongs, spits like the thorn that is found in Najd and is known as Sa'dan. The believers would then pass over within the twinkling of an eye, like lightning, like wind, like a bird, like the ...